With improving dietary habit and increasing Western diet, high-calorie, high-fat diets are ingested at increasing opportunities. Excessive lipid/fat ingestion causes obesity and serum lipid level elevation, and this increases the risk of onset of complications associated therewith.
Some substances are undegradable by the body and are therefore considered to prevent diabetes by restraining blood glucose level elevation and to be effective for dieting by restraining fat absorption. Indigestible dextrin (resistant dextrin) has been known as one of these substances (see Non Patent Literature (NPL) 1). Patent Literature (PTL) 1 proposes a lipid metabolism-improving agent containing a branched α-glucan having a specific structure. This agent is proposed as a lipid metabolism-improving agent containing dietary fibers that are safe even when ingested for a long time.
Advantageously, the indigestible dextrin does not impede mineral absorption and is approximately free of adverse effects. However, the indigestible dextrin has room for the further improvements in triglyceride decrease. In addition, the indigestible dextrin may cause diarrhea when ingested in a large amount.
Independently, soluble dietary fibers such as carboxymethylcellulose (CMC), indigestible dextrin, pectin, and polydextrose are used as food additives. These soluble dietary fibers are considered to have functions (i) to (iii) as follows. (i) The soluble dietary fibers increase the viscosity of intestinal contents and retard sugar absorption to thereby restrain postprandial abrupt elevation of blood glucose levels. (ii) The soluble dietary fibers adsorb bile acids and cholesterol and excrete them from the body to thereby restrain serum cholesterol level elevation. (iii) The soluble dietary fibers are fermented/decomposed in the intestinal tract to increase the amount of short-chain fatty acids to thereby promote the development of the intestinal epithelial cells. However, increase of intestinal bacterial groups including short-chain fatty acid-producing bacteria has not yet been investigated, except the increase typically in the case of fermented lactic-drinks.